1. Technical Field
The present invention relates to a polarizing element, a liquid crystal device, and an electronic apparatus.
2. Related Art
As one type of polarizing element, a polarizing glass is known. A polarizing glass can be composed only of an inorganic substance, and therefore, as compared with a polarizing plate containing an organic substance, the deterioration thereof due to light is significantly less. Therefore, a polarizing glass has drawn attention as an effective optical device in a liquid crystal projector whose brightness has been enhanced recently.
As a general polarizing glass, those described in JP-A-56-169140 are known, and a method for producing such a polarizing glass is as follows.
(1) A glass product having a desired shape is produced from a composition containing silver and at least one halide selected from the group consisting of chlorides, bromides, and iodides.
(2) The produced glass product is heated to a temperature which is higher than the strain point but not higher than the softening point of the glass by about 50° C. for a period of time sufficient to produce crystals of AgCl, AgBr, or AgI in the glass product, whereby a crystal-containing product is produced.
(3) The resulting crystal-containing product is elongated under stress at a temperature which is higher than the annealing point but lower than a temperature at which the glass has a viscosity of about 108 poises so that the crystals are elongated to have an aspect ratio of at least 5:1.
(4) The elongated product is exposed to a reducing atmosphere at a temperature which is higher than about 250° C. but not higher than the annealing point of the glass by about 25° C. for a period of time sufficient to develop a chemically reduced surface layer on the product. By this process, at least a portion of the elongated silver halide particles are reduced to elemental silver.
According to the production method described in JP-A-56-169140, the halide deposits uniformly in the glass product, but, in the reducing step, only the halide which is contained in the surface layer of the glass product can be reduced. Therefore, the halide remains in a central portion in the thickness direction of the glass product. Due to this, the transmittance of a polarizing element is decreased, and when the polarizing element is applied to a liquid crystal display device or the like, there is a possibility that a sufficient brightness cannot be obtained.
Many of the liquid crystal display devices capable of full-color display in the related art are provided with a color filter comprising a plurality of color material layers of, for example, red (R), green (G), and blue (B). In general, the polarization property of the polarizing element depends on the wavelength, and when one piece of polarizing element is used, the polarization properties with respect to red light, green light, and blue light are different. Therefore, a polarizing element having polarization properties averaged for red light, green light, and blue light was usually used. In other words, the polarization properties of the polarizing element were not optimized for each of red light, green light, and blue light. As a result, the liquid crystal display devices in the related art had a problem that sufficient brightness and contrast, and color reproducibility cannot be obtained.
JP-A-2004-256915 only describes that nanoparticles having an absorption wavelength peak in the visible range are used as a coating material, and the application thereof to a polarizing element is not suggested therein.